The present invention relates to a method and apparatus for evaluating the interruption of the winding of yarn on a textile winding machine.
In the winding of yarn from a supply package onto a cross-wound package, the yarn drawn from the supply package typically travels through a slub catcher-type yarn clearer which monitors the occurrence of certain out-of-limit situations such as sections of the traveling yarn which have a cross-section that is too thin or too thick. Swiss Patent Document No. 459,836 discloses an apparatus for restoring the winding operation of a winding station of a textile winding machine following a break in the travel of yarn in any one of three different situations. In one instance, a break in the yarn may be intentionally implemented through the control of a yarn cutting device by the slub catcher. In this instance, the slub catcher controls the yarn cutting device to sever the yarn at a location between the section of the yarn having the out-of-limits condition (i.e., too thin or too thick) and the supply package.
In a second type of yarn break situation which the apparatus disclosed in the Swiss Patent Document is adapted to handle, a break in the yarn occurs between the slub catcher and the cross-wound package. In both this situation and the situation in which the yarn is intentionally severed due to the detection of an out-of-limits section of the yarn, there is a length of yarn already unwound from the supply package and this unwound length of yarn can be readily engaged by, for example, a conventional suction-type yarn engaging arm, for guiding of the unwound yarn length to a splicing device at which the unwound yarn length from the supply package is spliced with a length of yarn from the cross-wound package. Since the unwound yarn length of the supply package, commonly referred to as the lower yarn, is available in the above-described two types of yarn break situations, there is no need to replace the supply package with a fresh supply package. In other words, it is presumed that the supply package is still capable of supplying the lower yarn.
In a third type of yarn break situation which the apparatus disclosed in the Swiss Patent Document is adapted to handle, a break in the yarn occurs between the slub catcher and the supply package. Since the yarn continues to be wound onto the cross-wound package until the slub catcher indicates that the yarn is no longer traveling therethrough, the lower yarn below the location of the yarn break has already fallen under its own weight before the slub catcher can activate an appropriate component such as, for example, a yarn brake, to engage the lower yarn. The apparatus of the Swiss Patent Document evaluates this third type of yarn break as an indication that the supply package must be exchanged for a fresh supply package and a package exchange operation is accordingly implemented. However, the supply package may still have a quantity of yarn wound thereon--in other words, the supply package is not fully unwound--and so the replacement of the supply package with a fresh supply package is premature, necessitating additional steps that must be undertaken to further wind the remaining yarn of the supply package during another winding operation or to strip the remaining yarn to dispose the tube of the present supply package in an empty status for building another yarn package thereon.
German Patent Document 21 53 370 discloses a yarn feeler which is disposed for sensing the travel thereover of yarn at a location between the supply package and a yarn brake. The yarn feeler controls the operation of the yarn brake to engage the lower yarn in the event of a yarn break. However, yarn feelers of this type are typically relatively sensitive and will falsely indicate the occurrence of a yarn break even though no actual break has occurred. For example, the presence of soil and other debris may prompt the yarn feeler to falsely determine that a yarn break has occurred.
Accordingly, the need still exists for an apparatus which minimizes the number of supply packages still having remaining yarn which are prematurely exchanged for fresh supply packages in winding operations. Additionally, the need still exists for an apparatus which minimizes the number of attempts to engage an upper yarn of a cross-wound package during a procedure to restore the winding operation of a winding station.